In variadic functions we still do the cast. In POSIX, it's not
necessary, since NULL is required to be of type 'void *', and 'void *'
is guaranteed to have the same alignment and representation as 'char *'.
However, since ISO C still doesn't mandate that, and moreover they're
doing dubious stuff by adding nullptr, let's be on the cautious side.
Also, C++ requires that NULL is _not_ 'void *', but either plain 0 or
some magic stuff.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
- Since strncpy(3) is not designed to write strings, but rather
(null-padded) character sequences (a.k.a. unterminated strings), we
had to manually append a '\0'. strlcpy(3) creates strings, so they
are always terminated. This removes dependencies between lines, and
also removes chances of accidents.
- Repurposing strncpy(3) to create strings requires calculating the
location of the terminating null byte, which involves a '-1'
calculation. This is a source of off-by-one bugs. The new code has
no '-1' calculations, so there's almost-zero chance of these bugs.
- strlcpy(3) doesn't padd with null bytes. Padding is relevant when
writing fixed-width buffers to binary files, when interfacing certain
APIs (I believe utmpx requires null padding at lease in some
systems), or when sending them to other processes or through the
network. This is not the case, so padding is effectively ignored.
- strlcpy(3) requires that the input string is really a string;
otherwise it crashes (SIGSEGV). Let's check if the input strings are
really strings:
- lib/fields.c:
- 'cp' was assigned from 'newft', and 'newft' comes from fgets(3).
- lib/gshadow.c:
- strlen(string) is calculated a few lines above.
- libmisc/console.c:
- 'cons' comes from getdef_str, which is a bit cryptic, but seems
to generate strings, I guess.1
- libmisc/date_to_str.c:
- It receives a string literal. :)
- libmisc/utmp.c:
- 'tname' comes from ttyname(3), which returns a string.
- src/su.c:
- 'tmp_name' has been passed to strcmp(3) a few lines above.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
It is Undefined Behavior to declare errno (see NOTES in its manual page).
Instead of using the errno dummy declaration, use one that doesn't need
a comment.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
* lib/gshadow.c: Remove __setsgNIS() -never used).
* lib/gshadow.c: Avoid multi-statements lines.
* lib/gshadow.c: Avoid assignments in comparisons.
* lib/gshadow.c: ptr[nelem] is a string. Initialize it to NULL
instead of '\0'.
* lib/gshadow.c: Add brackets and parenthesis.
* lib/gshadow.c: The size argument of strncpy is a size_t and the
size argument of fgets is an int.
Files with no license use the default 3-clauses BSD license. The copyright
were mostly not recorded; they were updated according to the Changelog.
"Julianne Frances Haugh and contributors" changed to "copyright holders
and contributors".
